An enclosure includes a housing and a sealing unit that fits within a sealing unit opening of the housing. The sealing unit provides a seal around cable ports and provides a peripheral seal between the housing and the sealing unit. The sealing unit can include a sealant arrangement and an actuation arrangement for pressurizing the sealant arrangement within the sealing unit opening. The actuation arrangement can include inner and outer pressurization structures between which the sealant arrangement is positioned. The actuation arrangement includes first and second actuators each movable between a non-actuated position and an actuated position. When the first and second actuators are moved towards the actuated positions, the first and second actuators generate first and second seal pressurization forces that press the sealant arrangement between the first and second pressurization structures, and the first and second seal pressurization forces are transferred through respective first and second springs.